RE: Bug in ColorFunctionScaling ???
- To: mathgroup at smc.vnet.net
- Subject: [mg39439] RE: [mg39386] Bug in ColorFunctionScaling ???
- From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
- Date: Sat, 15 Feb 2003 01:42:17 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
>-----Original Message----- >From: Cesar Guerra [mailto:guerra_cesar at yahoo.com] To: mathgroup at smc.vnet.net >Sent: Thursday, February 13, 2003 10:54 AM >To: mathgroup at smc.vnet.net >Subject: [mg39439] [mg39386] Bug in ColorFunctionScaling ??? > > > > >Hi math group > >working with the matrix given at the end of this mail I had >troubles trying to visualize it. For instance > >ListDensityPlot[matrix] > >works too bad as can be seen using a 3D chart > ><<Graphics`Graphics3D` > >BarChart3D[matrix] > >I got the correct density plot when I scaled the matrix >elements by hand: > >min = Min[matrix]; > >max = Max[matrix]; > >ListDensityPlot[matrix,ColorFunctionScaling->False,ColorFunctio >n->(GrayLevel[(#-min)/(max-min)]&)]; > >The question: is it a bug or I lost something in the way? A >similar problem arises with many matrices that I generated in >which there are many numbres close to zero. > >Regards.. Cesar, > >Well here is the matrix. Sorry because of the horrible format > [...] > > Cesar, observe: In[8]:= dp = ListDensityPlot[matrix]; In[10]:= Cases[Graphics[dp], Raster[_, _, zrange_] :> zrange, Infinity] // InputForm Out[10]//InputForm= {{0., 0.00009202801719751475}} In[11]:= Through[{Min, Max}[matrix]] Out[11]= {6.532730362808272`*^-22, 0.9373917995816773`} This is the discrepancy; the suspicion is, this comes from some (mostly) convenient automatism: In[13]:= Options[dp, {ColorFunction, ColorFunctionScaling, PlotRange}] Out[13]= {PlotRange -> Automatic, ColorFunction -> Automatic, ColorFunctionScaling -> True} Indeed... In[14]:= ListDensityPlot[matrix, PlotRange -> All]; ...gives what you do miss. -- Hartmut Wolf